Companions

The Moon, two stars, and two planets all look a bit chummy tonight. As night falls, Mars stands to the upper right of the Moon, and looks like a fairly bright orange star. The planet Saturn and the star Spica are a little farther to the upper left of the Moon, with Saturn higher in the sky.

The other star is pretty faint, but under a fairly dark sky it’s easy to pick out because it’s especially chummy with Mars. Tonight, it’s separated from the planet by a bit more than the width of the Moon, and it’ll be even closer tomorrow night.

The star is Beta Virginis, one of the brighter stars of Virgo. Spica is Virgo’s brightest star, so there’s quite a drop-off between it and the constellation’s other leading lights.

Beta Virginis is also called Zavijava, from an ancient Arabic name that meant “the turn.” It referred to a bend in a string of stars. The name originally applied to a different star, but somehow migrated to Beta Virginis.

The star is about 36 light-years away, and it’s quite similar to the Sun. It’s a bit bigger and heavier, which makes the star about three times brighter than the Sun. It’s roughly the same age as the Sun, which means it’s in the same stage of life — it’s steadily “burning” the hydrogen in its core to make helium. Because it’s a bit more massive than the Sun, though, Beta Virginis will use up its hydrogen more quickly — ending its life at a much younger age than the Sun will.

More about the Moon and its companions tomorrow.

Script by Damond Benningfield, Copyright 2012

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